1. Field of the Invention
The present invention pertains to a vacuum conveyor apparatus that stabilizes multiple single file lanes of objects conveyed on a conveying surface of the apparatus by directing vacuum pressure through multiple slots beneath the conveying surface where the multiple slots are aligned with the multiple lanes of objects on the conveying surface.
2. Description of the Related Art
Conveying systems for conveying multiple objects, for example lightweight blow-molded plastic bottles being manufactured at a manufacturing facility, typically include portions of the conveying system that quickly convey multiple side-by-side lanes or streams of the bottles on a belt conveyor from one station of the conveying system to another station. For example, multiple side-by-side lanes of bottles may be conveyed on a conveying belt surface from a blow molding station where the bottles are formed to a downstream palletizing station where the bottles are arranged on pallets. Conveying the bottles in multiple side-by-side lanes or streams increases the overall efficiency of the conveying system as opposed to conveying a single lane of bottles. The multiple lanes of bottles are maintained in their side-by-side positions on the conveying belt surface by guide rails positioned over the belt surface. The guide rails extend along the belt surface length and along the opposite sides of each lane of bottles.
The multiple lanes of bottles on a first conveyor are often conveyed to a row former. The row former separates a set number of bottles from each of the lanes and forms them into parallel rows that then are moved by the row former to a second conveyor. A typical row former includes a plurality of straight, parallel bars. The spaces between adjacent pairs of bars receive the set number of bottles when forming them into a row. The row former bars generally align with the guide rails of the first conveyor when the row former bars are lowered as the row former area receives the bottles from the conveyor. The row former also has a conveying belt surface that is aligned with and moves in the same direction as the first conveyor belt surface.
The first conveyor typically has gates positioned at the ends of the conveyor guide rails and adjacent the row former bars. The gates are controlled to move between opened and closed positions. In the closed positions the conveying belt surface of the first conveyor continues to move and the gates prevent the multiple lanes of bottles between the guide rails from moving into the row former area. When the gates are operated to move to their opened positions they allow a set number of bottles from each of the selected multiple lanes of bottles on the first conveyor to pass the gates and move into the row former area. As the gates become opened, the first conveyor and the second conveyor are then accelerated to quickly move the desired number of bottles or containers in the selected lanes past the gates and are then decelerated as the predetermined numbers of bottles in the lanes near completion. Once the set number of bottles has passed the gates, the gates are then operated to move to their closed positions where the gates again hold back the multiple lanes of bottles as the conveying belt surface continues to move.
The end of the row former has stop surfaces between each pair of adjacent row former bars. The stop surfaces stop the movement of the released bottles as the conveying belt surface of the row former continues to move. With the desired number of bottles per rows having been achieved in the row former area and with the row former simultaneously arriving downwardly on opposite sides of the rows, the row former, with the arrayed rows of bottles, then moves in a direction perpendicular to the rows of bottles and sweeps the rows of bottles across the row former belt surface and onto a conveying surface of the second conveyor. The bars of the row former while moving forward also simultaneously move upward from the second conveyor surface, leaving the numbers of bottles in the first arranged rows of bottles on the second conveyor surface. The row former is then moved in the opposite direction back to its position where the row former bars are again aligned with the/first conveyor guide rails. The row former then moves downwardly, aligning the spacings between the row former bars with the multiple lanes of bottles that have been released by the gates of the first conveyor. When the set number of bottles passes the gates, the gates are again moved to their closed positions where the gates hold back the multiple lanes of bottles on the first conveyor. The row former reaches its lowered position over the row former area conveying belt surface just prior to the released numbers of bottles reaching the stop surfaces of the row former. The movement of the row former described earlier is then again repeated, leaving the numbers of bottles in the second arranged rows on the second conveyor surface. This movement of the row former is repeated in forming two dimensional arrays of bottles on the second conveyor.
In prior art conveyor systems, the configurations of some plastic blow molded bottles have presented problems. Bottles having a much larger height dimension relative to their width dimension tend to be unstable. Additionally many blow molded bottles are formed with bottom surfaces having recessed center areas or some other configurations that reduces the contact areas of the bottom surfaces with the conveyor belt surface. These make the bottles unstable.
When the lanes of bottles are released from the gates of the first conveyor and move onto the conveying surface of the row former, the row former conveying surface at first accelerates to quickly load the multiple lanes of bottles into the row former area and then quickly decelerates just before the multiple lanes of bottles come into contact with the stop surfaces at the end of the row former. This quick acceleration and deceleration of the multiple lanes of bottles on the row former conveying surface can result in bottles conveyed into the row former area falling over before the row former bars are lowered over the lanes of bottles.
Still further, when the multiple lanes of bottles moved into the area of the row former on the row former conveying surface contact the stop surfaces at the end of the row former, the contact can result in bottles at the ends of the multiple lanes of bottles being knocked over.